The purpose of this contract is to conduct a randomized, double-blind, controlled trial of a combination of low-dose, continuous hormone replacement (o.d mg/day conjugated equine estrogens, +2.5 mg/day medroxyrpogesterone) with alendronate (10mg/day). The two drugs will each be tested alone and in combination in estrogen deprived, osteopenic, postmenopausal women over 60 years of age. Each of the three groups will enroll 72 participants and follow them for three years. Calcium and Vitamin D supplements will be given to all participants throughout the study. The hypothesis that will be tested is that the combined therapy shows a greater bone effect than either drug given alone. The primary outcome measures will be spine bone mineral density, total hip bone mineral density, and total body bone mineral content.